I think the 3DS will have more great titles to come, but the ones at the top of my head are SMT4, Project X Zone (almost coming outta Japan and ty Namdai for listening), Tales of The Abyss. Btw, this is a very interesting thread.

I'd say...
Fire Emblem Awakening, Rhythm Thief and the Emperor's Treasure, Theatrhythm Final Fantasy ( trust me, it's not essential to know anything about the series to play the game.), Kid Icarus Uprising,Tales of the Abyss, HarmoKnight( get it on the Eshop), Professor Layton and the Miracle Mask, and Super Mario 3d land.